(1) Field of the Invention
The present invention relates to acoustic wave systems and devices, and more particularly to sonobuoys with component activating or deployment means.
(2) Brief Description of the Prior Art
Expanding mission requirements caused by the increased frequency of regional conflicts and state-sponsored terrorism, have forced fast attack submarines into littoral operations. Submarines are well suited for this type of mission, allowing on-station, forward deployment, without the vulnerability, or force telegraphing of a surface ship and the associated political and tactical ramifications. Whether alone, or acting in conjunction with a battle group, the submarine will increasingly be called on to patrol and prosecute hostile contacts in this challenging environment as well as deliver precision missile strikes on inland targets.
Hostile submarines are a serious threat to friendly submarines, as well as to friendly surface ships. One such danger comprises diesel-electric type submarines, commonly known as diesel boats. While relatively cumbersome for extended, deep-water operations, diesel boats are well suited for coastal defense in the littoral regions. Relatively small, inexpensive and quiet (when operating on battery power), diesel boats can lie in wait for an approaching battle group, or patrol quietly just off the shore in search of submarines and surface craft.
While fast attack submarines possess many operational advantages, there are still considerable risks associated with entering shallow or xe2x80x9cbrownxe2x80x9d water to search for enemy submarines. A nuclear-powered fast attack submarine would prove a priceless propaganda trophy for any hostile country. Many of the same risks would attend operations by surface ships in such waters.
Another submarine hunting method is using an Anti-Submarine Warfare (ASW) helicopter launched from a surface ship at standoff distance. This method, however, also entails considerable risk due to the amount of time the helicopter must spend hovering, while dipping sonar to locate the hostile submarine, leaving it seriously vulnerable to fire from shore or from small craft.
The prior art also discloses the use of buoys or other discrete deployable devices for housing a sonar apparatus or other sensors that may be used to monitor an area for hostile submarine threats. U.S. Pat. No. 4,186,374 to Ouellette, for example, discloses a transducer housing for an air dropped sonar transducer including a smooth cylindrical case for stowage on board an aircraft. The case is formed with a separation device, which permits ejection of the transducer from the case upon impact with the surface of the ocean, the device being formed of tabs on the case and chamfers on a cover plate of the case. The impact of the water on the cover plate is directed by the chamfers against the tabs to spread them apart thereby releasing the cover plate and the transducer. Pins on the cover plate project through apertures in the tabs and press against the side of the apertures with a preset force to essentially lock the tabs to the plate until the preset force is overcome by the water impact.
U.S. Pat. No. 5,691,957 to Spiesberger discloses an acoustic tomography telemetry system and method that allows spatially averaged ocean temperatures to be measured in real-time. This system includes autonomous acoustic sources mounted on subsurface mooring and receivers that are either suspended from drifting surface buoys or cabled to shore. The telemetry method largely eliminates, in real-time, corruption of acoustic travel times due to wander of the source""s mooring by shifting the start times of tomographic transmissions. Corrections to source wander are obtained without expending battery energy over and above that used in conventional tomography experiments. Standard techniques are used to correct clock errors at the source in real-time.
U.S. Pat. No. 5,973,994 to Woodall discloses a sonobuoy device for tracking and targeting submarines. The sonobuoy device consists of a sonobuoy having aft and forward sections interconnected with each other, fin means mounted on the aft section for flight stabilization of the device during travel above water from the platform, separation means responsive to impact of the device with the water upon completion of the travel thereof for separating the sections of the device from each other, payload means within the forward section of the device for listening for an acoustical signal in response to submergence thereof within the water following the separation of the sections of the device, flotation means mounted within the device and inflated in response to the impact with the water for anchoring the payload means and tethering means connecting the flotation means to the payload means for limiting the submergence thereof while anchored by the flotation means to a predetermined depth at which the payload means receives an acoustical signal. An apparatus comprised of a device with a launching system and a method for deploying the device also is disclosed.
A further improved means for efficiently and cost effectively deploying sonar buoys with a low degree of risk to friendly forces is still needed.
It is an object of the present invention to provide a device and method for efficiently and cost effectively monitoring littoral and other waters for enemy submarines and other threats with a low degree of risk to friendly forces.
It is a further object of the present invention to provide a means for a submarine-launched cruise missile to lay a wide-area field of sonar buoys from a standoff distance.
This and other objects are accomplished by the apparatus of the present invention, which is a sonar buoy adapted to be deployed by a cruise missile. This sonar buoy includes a flotation device for keeping a portion of the buoy afloat, a hydrophone, a transmitter for communicating contact and position information and a releasable means for attaching the sonar buoy to the cruise missile. By means of this device, a means of monitoring littoral and other waters for enemy submarines and other threats is provided with a low degree of risk to friendly forces.
Preferably, this sonar buoy may be deployed by a submarine-launched Tomahawk UGM 109D cruise missile outfitted with sonar buoys. Originally designed to deliver small sub-munitions to multiple targets, the UGM 109D features four payload modules, each holding six packs of sub-munitions. The Tomahawk sonar buoy device replaces each pack with a payload shell containing a sonar buoy.
This apparatus allows a submarine to lay a wide area field of sonar buoys from a standoff distance, allowing anti-submarine warfare (ASW) forces to pinpoint and track hostile contacts from a safe range before attacking.